Precipitation variability and trends in Southern Brazil (1991–2020)

Abstract Understanding climate variability patterns is essential to address the challenges of climate change. This study investigated precipitation variability and extremes in the southern of Brazil between 1991 and 2020. The analysis, conducted with climate indices, revealed a heterogeneous distribution of precipitation, with specific concentrations and extreme events across six homogeneous sub-regions. Annual mean precipitation showed a disparity of 692 mm between the northern coastal and southern areas. Seasonal trends were identified with increases in extreme rainfall during some seasons, while autumn exhibited an overall decrease. The variability and occurrence of extremes underscore significant internal differences within the subtropical climate, suggesting the need for potential revisions to its traditional classification. These findings provide detailed insights into precipitation dynamics, with direct implications for water resource management, agricultural planning, management and practices, and developing more effective adaptive strategies. The clustering approach was innovative in identifying spatial patterns that reflect the complexity of the subtropical climate in Southern Brazil, emphasizing the importance of considering local specificities in decision-making and policy development.